Java 以编程方式设置 Logback Appender 路径
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Setting Logback Appender path programmatically
提问by yshalbar
I'm trying to set Logback appender path programmatically. (RollingFileAppenderwith FixedWindowRollingPolicy to be exact)
我正在尝试以编程方式设置 Logback appender 路径。（确切地说是带有 FixedWindowRollingPolicy 的RollingFileAppender）
I'm doing this because I want to enable my users to set the log path in a preference dialog (Eclipse RCP)
我这样做是因为我想让我的用户在首选项对话框（Eclipse RCP）中设置日志路径
I've tried something like this, but I doesn't change the log path from what's defined in the configuration file:
我试过这样的事情，但我没有改变配置文件中定义的日志路径：
Logger logback_logger = (ch.qos.logback.classic.Logger)LoggerFactory
.getLogger(org.slf4j.Logger.ROOT_LOGGER_NAME);
RollingFileAppender<ILoggingEvent> rfappender =
(RollingFileAppender<ILoggingEvent>)logback_logger.getAppender("FILE");
rfappender.setFile(newFile);
FixedWindowRollingPolicy rollingPolicy =
(FixedWindowRollingPolicy)rfappender.getRollingPolicy();
rollingPolicy.setFileNamePattern(newPattern);
采纳答案by yshalbar
Using system properties and reloading the configuration file seems cleaner:
使用系统属性并重新加载配置文件似乎更清晰：
change the logback.xml file:
更改 logback.xml 文件：
<file>${log_path:-}myfile.log</file>
....
<FileNamePattern>${log_path:-}myfile.%i.log</FileNamePattern>
This will set the default location to the working directory. Then, use:
这会将默认位置设置为工作目录。然后，使用：
System.setProperty("log_path", my_log_path);
//Reload:
LoggerContext lc = (LoggerContext) LoggerFactory.getILoggerFactory();
ContextInitializer ci = new ContextInitializer(lc);
lc.reset();
try {
//I prefer autoConfig() over JoranConfigurator.doConfigure() so I wouldn't need to find the file myself.
ci.autoConfig();
} catch (JoranException e) {
// StatusPrinter will try to log this
e.printStackTrace();
}
StatusPrinter.printInCaseOfErrorsOrWarnings(lc);
回答by yshalbar
Looking at the Logback code, I have found a workaround:
查看 Logback 代码，我找到了一个解决方法：
rollingPolicy.stop();
rfappender.stop();
rollingPolicy.start();
rfappender.start();
This causes Logback to use the new definitions. It still feels like a workaround, though.
这会导致 Logback 使用新定义。不过，它仍然感觉像是一种解决方法。
回答by Ceki
Once you programmatically configure your appender, you need invoke its start()method. If the appender has sub-components, invoke start()on the sub-components first. You then add the appender to the logger of your choice.
以编程方式配置 appender 后，您需要调用它的start()方法。如果 appender 有子组件，先调用start()子组件。然后将 appender 添加到您选择的记录器中。
Here is an example:
下面是一个例子：
import ch.qos.logback.classic.Logger;
import ch.qos.logback.classic.encoder.PatternLayoutEncoder;
import ch.qos.logback.core.rolling.FixedWindowRollingPolicy;
import ch.qos.logback.core.rolling.RollingFileAppender;
import ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy;
import ch.qos.logback.core.util.StatusPrinter;
import org.slf4j.LoggerFactory;
import ch.qos.logback.classic.LoggerContext;
public class Main {
public static void main(String[] args) {
LoggerContext loggerContext = (LoggerContext) LoggerFactory.getILoggerFactory();
RollingFileAppender rfAppender = new RollingFileAppender();
rfAppender.setContext(loggerContext);
rfAppender.setFile("testFile.log");
FixedWindowRollingPolicy rollingPolicy = new FixedWindowRollingPolicy();
rollingPolicy.setContext(loggerContext);
// rolling policies need to know their parent
// it's one of the rare cases, where a sub-component knows about its parent
rollingPolicy.setParent(rfAppender);
rollingPolicy.setFileNamePattern("testFile.%i.log.zip");
rollingPolicy.start();
SizeBasedTriggeringPolicy triggeringPolicy = new ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy();
triggeringPolicy.setMaxFileSize("5MB");
triggeringPolicy.start();
PatternLayoutEncoder encoder = new PatternLayoutEncoder();
encoder.setContext(loggerContext);
encoder.setPattern("%-4relative [%thread] %-5level %logger{35} - %msg%n");
encoder.start();
rfAppender.setEncoder(encoder);
rfAppender.setRollingPolicy(rollingPolicy);
rfAppender.setTriggeringPolicy(triggeringPolicy);
rfAppender.start();
// attach the rolling file appender to the logger of your choice
Logger logbackLogger = loggerContext.getLogger("Main");
logbackLogger.addAppender(rfAppender);
// OPTIONAL: print logback internal status messages
StatusPrinter.print(loggerContext);
// log something
logbackLogger.debug("hello");
}
}
The above code is the programmatic expression of the steps taken by the logback's XML configurator, i.e. Joran, when it parses the RollingFixedWindow.xmlfile.
上面的代码是 logback 的 XML 配置器（即 Joran）在解析RollingFixedWindow.xml文件时所采取的步骤的编程表达。
